How to Unlock Stone Mask and Its Matching Evolution

How to unlock Stone Mask

The condition shown for Stone Mask on the official Steam achievements page is to find the Stone Mask. Complete that requirement during a run first.

What to do

1. Prepare the character or pickup named in the requirement.
2. Find the Stone Mask.
3. After the run, check whether the achievement or unlock has registered.

This answer follows the wording on Steam's official achievement page. Achievement labels and notification behavior can differ by platform, so this guide does not assume an unverified menu flow.

Matching evolution

Stone Mask pairs with Gatti Amari for its evolution into Vicious Hunger. This pairing is verified; check the evolution list for any additional weapon-level or chest requirements.

If the condition does not register

• Confirm that the specified character was used.
• Check that the required time or level was reached before ending the run.
• For a find requirement, confirm that the item was collected during the stage.
• For the six-weapon requirement, check whether any held weapon remained unevolved.

Read next

• Base passive items
• Achievements and unlocks

Source

• Official Steam achievements page